A number of mailbox devices are adapted for mounting on an upright member such as a pole or post. In such a configuration, there are several situations in which it is advantageous to provide for varying the orientation of the mailbox by providing for rotation of the mailbox about a vertical axis. One such situation arises when the mailbox is configured such that the mail is deposited by the postal service through a rear door or opening, while the mail is retrieved by the postal patron through a front door or opening. Such configurations are particularly common when a multiplicity of mailboxes are joined in a single unit such as a Neighborhood Delivery and Collection Box Unit or NDCBU. In such a unit, postal workers can gain access simultaneously to a multitude of mailboxes through a rear panel, which is opened by operation of a lock. Typically, all such locks in a geographical area such as a city are operated by a single configuration of a key which is carried by all postal workers. In this way, postal workers can be assigned to a variety of routes within a city without the necessity for obtaining a different key for each route.
The postal patron obtains access to a particular assigned mailbox within an NDCBU by means of a key which opens the lock on the front panel of his mailbox and no other.
Providing for rotation of a mailbox system such as an NDCBU which has both front and rear access doors is advantageous when it is impractical or expensive to provide a working area such as a driving space for the postal worker and postal patron both at the rear and at the front of the mailbox unit. For example, when space is at a premium, it may be desirable to mount a mailbox unit in close proximity to a building, fence or other obstruction. In such a case, providing for rotation of the mailbox unit about a vertical axis allows access to both front and rear mailbox entries despite the presence of a nearby obstacle. The presence of a snowbank may similarly obstruct access to some portion of the mailbox such as when the mailbox is mounted near a route which is cleared by snow plow.
Even in the absence of physical obstacles to portions of the mailbox, it may be more cost effective to provide for rotation of the mailbox than to provide facilities for access to both the front and the rear of the mailbox. In particular, a postal service may require the installation of a surface such as a concrete pad for use by the postal workers when delivering mail through a rear entry mailbox. Thus, a non-rotatable two-entry mailbox would require provision of a surface both in front and in the rear of a mailbox. Providing for rotation of such a mailbox eliminates the need for one of these two surfaces.
When the mailbox is designed for access from a vehicle on a roadway, providing for rotation of the mailbox allows vehicle-based access by both the postal worker and the postal patron.
Various other advantages can arise from providing a rotatable mailbox, even when the mailbox has only a single door. For example, in some places the orientation of the mailbox serves to provide a signal that the mailbox contains mail for collection or mail that has been delivered.
When a rotatable mailbox is provided for one of the reasons above, or for other reasons, it is desirable to include a mechanism for locking the mailbox in one or more orientations. In particular, it is desirable to provide a mechanism for locking the mailbox in an orientation that provides access to the postal patron. In this manner, the postal worker, after depositing mail in the appropriate mailboxes, may orient the mailboxes so that the postal patrons may collect their mail, and may lock the mailbox in this orientation so as to prevent tampering with the mailbox or shifting of the orientation of the mailbox in response to wind or other forces.
In providing a rotatable mailbox which can be locked in a preferred orientation, a number of problems arise, owing partly to certain characteristics of locks which are commonly used in the postal delivery service. As noted above, it is common for postal locks in a given geographical area to be of a single configuration, allowing for common keying of such locks. Locks which are typically used in postal delivery are characterized by a mechanism in which inserting a key into the lock allows the postal worker to turn the key and thus withdraw a bolt allowing a mailbox door to be opened. After depositing or retrieving mail, the mailbox door is shut and the key is turned so as to once more extend the lock bolt. In conventional postal locking mechanisms, such extension of the bolt engages the postal lock. Conventional mechanisms, when applied to a rotatable mailbox, thus present two unattractive alternatives. The postal worker may carry two keys, one to unlock the rotation mechanism lock to allow access to the rear of the mailboxes, and a second key to open the rear of the mailbox. Alternatively, the mechanism may be lockable in its rear-access position, so that the postal worker must unlock the rotation mechanism, rotate the mailbox to the rear-access position, relock the rotation mechanism in this position, remove the key, use the key on the rear door of the mailbox, remove the key from the rear door lock, insert the key in the rotation lock, unlock the rotation mechanism, rotate the mail box to the front access position, and relock the rotation mechanism in the front access position. The first alternative requires doubling the supply of keys in circulation, presenting both a higher cost and an increased risk of postal keys falling into unauthorized hands. The two keys operate in locks which are physically spaced apart, and thus the keys typically can not be placed on a single keychain, thus increasing the risk of loss. The second alternative creates an undesirable proliferation of steps involved in delivery of mail, reducing efficiency and increasing costs of delivery.
Another characteristic of the type of locks commonly used in postal applications is that such locks have a tendency to bind if the nut and bolt mounting means is over-tightened. However, a lock for a rotatable mailbox must be quite securely mounted in order to avoid tampering and to prevent wear and/or slippage which might result from excessive play between the bolt of the lock and the locking mechanism.
Mechanisms have been proposed for latching a rotatable mailbox in a particular orientation which involve using a spring to bias a horizontally oriented bolt so that the bolt will move horizontally into a notch on a vertically stationary ring when the bolt aligns with the notch.
Mechanisms for securing a rotatable mailbox which depend upon springs for the required latching force have been found unsatisfactory because such mechanisms are susceptible to mechanical failure and/or corrosion, rusting or clogging caused by exposure to water, mud, or snow. These latching mechanisms must be either readily accessible for maintenance purposes, thus increasing both the risk of tampering and exposure to the elements, or must be covered or protected in some manner, thus increasing the costs of maintenance because of the need for removing such covering or protection before performing maintenance. Maintenance requirements are particularly acute when the mechanism is intended for use with an NDCBU, since such a unit is typically in use on a nearly daily basis and, further, is typically heavy, compared to a single mail box unit.
Further, it has been found that spring-dependent latching mechanisms lack the strength which is necessary for a practical rotatable mailbox pedestal. A rotatable mailbox pedestal should exhibit sufficient strength to maintain its structural integrity even when subjected to strong forces. Preferably a mailbox pedestal should be able to withstand a force by 500 lbs pull applied to its apex in any direction.
Accordingly, it is an objective of this invention to provide a pedestal for rotatably mounting a mailbox which can be unlocked for rotation to a rear orientation and which will relock automatically (i.e. without further use of a key) upon rotation to a forward orientation.
It is also an object of this invention to provide a pedestal for a rotatable mailbox which can be unlocked using the same key carried by postal workers for unlocking the mailboxes.
It is a further object of this invention to provide means for mounting a lock for a rotatable mailbox pedestal which provides security and strength along with ease of installation and operation.
It is another object of this invention to provide a locking means for a rotatable mailbox pedestal which is simple in operation, avoiding dependence on springs so as to reduce maintenance costs while maintaining security.